The invention relates to a device for transmitting data between a data transmission device of a vehicle and a data transmission device of a communication network as part of a charging process of an electrical energy store of the vehicle.
Charging an energy store of an electrically operated vehicle requires an exchange of communication between the vehicle and the charging device. As part of such a communication, status and control values are transmitted which are needed for the technical charging process. Just as well, information can also be transmitted which is needed for paying/accounting for the charging process. Furthermore, value-added services such as, e.g., a flash update of multimedia contents can also be transmitted to and from the vehicle.
It is contemplated to use a digital communication between the vehicle and the charging station for the applications described above. This can be based on power line technology according to ISO 15188 and is known by the term power line communication (PLC). The charging process of electrical vehicles is standardized primarily in ISO 15188. Apart from the purely technical subjects such as controlling the charging process (by specifying e.g. voltages, currents and duration), the accounting process is also the motivation for transmitting vehicle data. Apart from the charging process per se, various targets are pursued such as, e.g., linking to the home networking for Internet, video and Internet radio with very high bandwidths during the charging phase. For the ranges mentioned last, products with power line technology with 14 MBd, 85 MBd or currently 200 MBd are available today commercially. Plannings go beyond 200 MBd. These standards are combined under the term Homeplug Audio/Video (HPAV) in the further text. PLC technology is a transmission technology which uses various modulation methods, e.g. QAM and carrier frequency methods, and can use as transmission medium the power lines (conductor L and neutral conductor N) or any available conductor.
In addition, a method according to the new Homeplug Greenphy 1.1 (HPGP1.1) is planned for the ISO standard ISO 15118. This standard uses from the available Homeplug standards only a restricted subset of features and a restricted bandwidth. The transmission for ISO 15118 is carried out not on a power line but on a separate signal line also used for other purposes (Control Pilot CP) and the protective earth (PE). The signal line CP is used for very simple charging systems and enables a charging process to be controlled in the normal case only with a +/−12V PWM signal with 1 kHz clock rate. This original signal CP, however, is not relevant for the further description.
In HPGP, only those modulation methods are used which are particularly robust against disturbances. The bandwidth is limited to 10 MBd. HPGP operates with up to 1055 carriers in the frequency band from 1.8 MHz to 30 MHz. The design of the HPGP standard is such that Homeplug-compliant PLC methods can communicate with one another guaranteed. HPGP and HPAV can then communicate with one another with maximally 10 MBd or with a guaranteed 7% proportion of the HPGP on a power line occupied by HPAV.
Due to the EMC regulations for vehicles and restrictions in various countries, direct communication between the charging station and the vehicle via a power line is not possible. The PLC communication in ISO 15118 is, therefore, applied on the abovementioned control pilot (CP) signal line. The defined return conductor is the protective earth (PE). Apart from this separation, it is necessary to lower the level of the transmitting power of the PLC modem for ISO 15118 which communicates with the vehicle very widely in order to cause no EMC disturbances in the vehicle itself and environment. It is particularly the demands on the vehicle manufacturers as part of the motor vehicle licensing regulations which play a great role in this case. For this reason, a further router or a gateway is needed in the charging column apart from the PLC modem for ISO 15118, which router or gateway implements communication with the Internet in order to implement bidirectional communication between the vehicle and the Internet.
A charging station which has an HPGP modem and the logical coupling with an HPAV modem previously required the expenditure of two complete modems and corresponding logic for coupling between the two modems with respect to signals, e.g. by means of a control computer. The charging station becomes technically elaborate and expensive, as a result.
It is the object of the present invention to specify a device for transmitting data between a data transmission device of a vehicle and a data transmission device of a communication network as part of a charging process of an electrical energy store of the vehicle, which device is constructionally and/or operationally improved.
This object is achieved by a device according to the features of patent claim 1. Advantageous embodiments are obtained from the dependent patent claims.
A device for transmitting data between a data transmission device of a vehicle and a data transmission device of a communication network as part of a charging process of an electrical energy store of the vehicle is proposed, the vehicle data transmission device being based on a first communication protocol having a first signal level and the communication network data transmission device being based on a second communication protocol having a second signal level. The device comprises a signal matching device with at least one first coupling transformer which, via respective coils, couples a data transmission device of a charging station with the data transmission devices of the vehicle and of the communication network with one another, the signal matching device matching the first signal level to the second signal level and conversely.
The device enables the levels of the vehicle data transmission device and of the communication network data transmission device to be matched. Since this only requires power amplifiers and passive components for level matching, the device can be implemented by means of simple means. In addition, a continuous information chain according to ISO 15118 can be implemented. The vehicle data transmission can be linked directly to a network which meets the standard of the communication network data transmission device. The intermediate step, described initially, of a router or bridge and two modems in the charging station is not necessary.
The data transmission device of the charging station can comprise a transmitting branch and a receiving branch which are in each case coupled with a coil of the first coupling transformer. The first coupling transformer can be a conventional PLC modem.
The data transmission device of the vehicle can be connected directly to one of the coils of the first coupling transformer. The first coupling transformer thus combines the lines of the transmitting and of the receiving branch and the lines for the communication with the vehicle data transmission device. This arrangement thus corresponds to the standard arrangement of a PLC modem.
The signal matching device can comprise a second coupling transformer which is coupled via a damping device with one of the coils of the first coupling transformer, the data transmission device of the communication network being coupled to a coil of the second coupling transformer. By this means, signals from the communication network data transmission device can be transmitted to the vehicle data transmission device, the signals being matched in their level via the signal matching device. Signals can be transmitted from the vehicle data transmission device to the communication network data transmission device, the signals being matched in their level via the signal matching device of the charging station.
The transmitting branch of the data transmission device of the charging station can be coupled with a further coil of the second coupling transformer via an amplifier, the amplifier, the second coupling transformer and the damping device forming a first signal branch between the data transmission device of the charging station and the first coupling transformer, and, between the data transmission device of the charging station and the second coupling transformer, a second signal branch being provided which couples a signal, having the opposite phase to the signal via the first signal branch, into the first coupling transformer. This allows interference effects to be compensated for.
The second level matching branch can comprise an amplifier, a third coupling transformer and a damping device, the phase rotation being effected by rotating the direction of coupling-in at one of the coils of the first coupling transformer. Due to the rotating of the coupling-in direction, the compensation by means of phase rotation of 180° can take place without additional components.
The components of the first and of the second level matching branch can be of identical construction. This allows interference effects to be compensated for reliably.
The amplifiers of the first and of the second level matching branch can be designed to amplify linearly in a predetermined frequency range by means of which the desired level matching can be achieved in a communication from the vehicle data transmission device to the communication network data transmission device.
The second signal level is higher than the first signal level. This means that a communication based on the first communication protocol of the vehicle data transmission takes place with a first, lower signal level than a communication based on the second communication protocol of the communication network data transmission device. The difference in level can be between −10 dB and −26 dB and especially −16 dB.
The first communication protocol and the second communication protocol can be based on a power line communication. For example, the first communication protocol can be Homeplug AV. The second communication protocol can be, e.g., Homeplug GreenPHY.
In summary, it is proposed to interconnect a signal matching device as a “bridge” between an HPGP network which is used for the communication to the vehicle and an HPAV network which is used for the communication to a communication network (such as, e.g., the Internet). By providing a plurality of conventional PLC modems according to the HPAV standard, the signal levels of the different networks can be matched and interference effects compensated for. This only requires power amplifiers and passive components for level matching and level compensation. The communication to the vehicle can take place seamlessly without an intermediate step via the PLC modems according to the HPAV standard. Requirements for EMC can be met separately for the HPGP and the HPAV network.
In the text which follows, the invention will be explained in greater detail by means of exemplary embodiments in the drawing, in which:
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of one or more preferred embodiments when considered in conjunction with the accompanying drawings.